BONE-MINERAL DENSITY OF THE RADIUS IN PATIENTS WITH OSSIFICATION OF THE CERVICAL POSTERIOR LONGITUDINAL LIGAMENT - A LONGITUDINAL-STUDY

Radial bone mineral density (BMD) in the distal one sixth and distal o ne third of the left radius was measured by single-photon absorptiomet ry (SPA) in patients with ossification of the cervical posterior longi tudinal ligament (OPLL). Twenty-three OPLL patients (15 men and 8 wome n) with mean initial age of 60.1 years were studied longitudinally for mean follow-up period of 3.9 years. Based on roentgenologic findings, the patients were divided into two groups, those with advancing OPLL and those with non-advancing OPLL. The final value of distal 1/6th BMD in the advancing group was significantly lower than its initial value , but no change of the value of the distal 1/3rd BMD was observed in e ither group. The final value of distal 1/6th BMD/distal 1/3rd BMD rati o in the advancing group was significantly decreased compared with its initial value. These results suggest that, in the advancing OPLL grou p, trabecular bone mass decreased while cortical bone mass remained un changed.